Mathematics and Science; the subtle and ubiquitous arts

OK, I mayby am quite nerdy, but I actually love Physics.

I've read some books about Einstein and his discovers and here is two facts I would like to talk about.

1. Every point of view is "worth the same". It doesn't matter if it is me standing still and he is moving towards me or if it is the opposite, it's the same.

2. Moving fast makes time going slower. (Since the speed of light can't change, than time must go faster and slower depending on speed, acceleration and gravity.)

So, at least in my eyes this is a paradox.
If I travels in a rocket in the speed of light for some years and come back to earth, than I'll be younger than my identical twin.
But why?
If every observer is right, than I think it was me who was standing still and the earth moving with high speed.
Than it must be my twin who is younger when the earth decides to come back to me with the speed of light after a few years.

And don't be afraid of telling me that I am wrong if I am!

EDIT: Splelling msistakes ifxed!
Dr_Phil
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Re: A question about general relativity

comperr
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Re: A question about general relativity

Thank you very much for the wikipedia-link!
I searched it, but forgot to search on the English version too!

I'll see if I can find such a book at the library here, I don't think I'll be able to understand it good enough on English..
..as you probably has noticed, English is not my native language!
Dr_Phil
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Re: A question about general relativity

I would recommend a book by Brian Green called the Elegant Universe. He does a pretty good job of discussing and using plain examples that you can relate to when it comes to relativity and the effects of the speed of light.
MrGrimm
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Re: A question about general relativity

MrGrimm wrote:I would recommend a book by Brian Green called the Elegant Universe. He does a pretty good job of discussing and using plain examples that you can relate to when it comes to relativity and the effects of the speed of light.

If you just want an explanation of the basic ideas, then this is an excellent book about string theory.

TheMindRapist
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Re: A question about general relativity

MrGrimm wrote:I would recommend a book by Brian Green called the Elegant Universe. He does a pretty good job of discussing and using plain examples that you can relate to when it comes to relativity and the effects of the speed of light.

dopamine10
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Re: A question about general relativity

This is a question about special relativity.

(scratches belly and points) 'theres yer problem'

tarantulas
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Re: A question about general relativity

As already said this is a question about time dilation and special relativity rather than general relativity.

The problem with your idea is that time doesn't change as such, simply the time observed by the observer changes. So if you were gone for 2 years according to a clock on earth, a clock inside your ship would show that you had been gone for less time. as far as using a reference frame where the earth moves at near c and you are stationary then from your frame of reference if two years had passed a clock on earth would show less time. This is because time and space dilation are dependent upon the reference frame chosen, much like momentum or velocity are dependent upon the reference frame.
novalyphe
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Re: A question about special relativity

Its acceleration that makes the difference. Two inertial reference frames are equivalent but in the case of the rocket ship acceleration has occurred. Accelerating reference frames are not inertial.
circuitboardsushi
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Re: A question about general relativity

lol I used to read up on this stuff myself all the time, very cool stuff and opens up your imagination. The problem is that you're trying to use every day logic, where the laws of general theory of relativity is counter intuitive by our everyday understanding of life in our universe anyway. There is proof of this concept in the particle accelerators. They took particles that normally have a very short life time < 1 second, and they were able to increase their lifetime to 30 seconds by zipping them around near the speed of light. Those particles are small scale time travelers into the future!!

Special relativity defines the nature of mass and time respect to their velocities. The nature of mass is not completely understood and there are 5 different versions of string theory competing against each other trying to unify quantum mechanics and general theory of relativity, but something happens to mass when you start moving it really fast near the light speeds. For one thing the mass starts to approach infinity and the length of the mass starts to decrease. now that I think about it that is interesting cause black hole singularities are defined to have infinite density and zero volume, which sounds like what is happening as mass is accelerated near light speeds. rofl now you got me thinking
xfelix
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